diff --git a/Lib/subprocess.py b/Lib/subprocess.py index 4955f77b60381f..68d41462237924 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -2077,6 +2077,10 @@ def _communicate(self, input, endtime, orig_timeout): self.stdin.flush() except BrokenPipeError: pass # communicate() must ignore BrokenPipeError. + except ValueError: + # ignore ValueError: I/O operation on closed file. + if not self.stdin.closed: + raise if not input: try: self.stdin.close() diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 9792d7c8983cd3..9275e444615af7 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -1062,6 +1062,19 @@ def test_writes_before_communicate(self): self.assertEqual(stdout, b"bananasplit") self.assertEqual(stderr, b"") + def test_communicate_stdin_closed_before_call(self): + # gh-70560, gh-74389: stdin.close() before communicate() + # should not raise ValueError from stdin.flush() + with subprocess.Popen([sys.executable, "-c", + 'import sys; sys.exit(0)'], + stdin=subprocess.PIPE, + stdout=subprocess.PIPE, + stderr=subprocess.PIPE) as p: + p.stdin.close() # Close stdin before communicate + # This should not raise ValueError + (stdout, stderr) = p.communicate() + self.assertEqual(p.returncode, 0) + def test_universal_newlines_and_text(self): args = [ sys.executable, "-c", diff --git a/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst b/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst new file mode 100644 index 00000000000000..a9bf5f80d80c9f --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst @@ -0,0 +1,3 @@ +When the stdin being used by a :class:`subprocess.Popen` instance is closed, +this is now ignored in :meth:`subprocess.Popen.communicate` instead of +leaving the class in an inconsistent state.